Public land mobile networks may be configured to control access by user equipment. This access control may prevent certain user equipment from initiating access to the network, responding to network pages, and the like. For example, in an emergency, a network service provider may control access in order to reduce network congestion. The base station serving a cell may broadcast information to user equipment, and this broadcast may indicate the types of user equipment barred access to the network. Specifically, a user equipment may be assigned to an access class (AC), such as 0 to 9. The assigned access class may be stored in the user equipment in a subscriber identity module (SIM), universal SIM, and/or any other secure storage mechanism. A user equipment may also be assigned to certain high priority access classes, such as access classes 11 to 15, which can also be stored in the SIM, USIM, and the like, and calls made as emergency calls are handled as access class 10.
When congestion or a network overload condition occurs, such as during an emergency, the network may broadcast which access classes are access barred, the duration of the barring, and/or the rate of the barring. The user equipment may receive the indication and then not allow accessing to the network, responding to a page, and/or the like. 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Service accessibility (Release 12), 3GPP TS 22.011, V12.0.0 (2013-03) (hereinafter TS 22.011) provides an example of a specification for access barring.